Systems for supplying, distributing and handling pressurized fluids are widespread, particularly in the context of manufacturing, machinery, internal combustion engines, and related systems. In an engine, a pressurized fluid system is often used for delivering combustible fuel to individual cylinders. It has been discovered that relatively high pressures of the fuel can assist in atomization of fuel spray to various ends, notably efficiency and reduction of certain emissions. The mechanisms used for initially pressurizing the fuel, distributing the fuel to fuel injectors, and generally containing fuel at any point in the system under relatively high pressures tend to be relatively sophisticated. Fuel pressures can be in excess of 300 MPa. It is also generally desirable to maintain fuel pressure for fuel injection within a relatively narrow range for controllability and predictability of operation.
Decades ago engineers developed a fuel system known as a common rail design where a fluid reservoir is maintained at or close to a desired pressure, A plurality of individual fuel injectors fluidly connected to the common rail can be supplied with the fuel at rail pressure and selectively operated to effect fuel injections. In more recent years, a variation on the common rail design was developed where a plurality of separate fuel accumulators are positioned fluidly between a common rail and each of a plurality of fuel injectors. The plurality of accumulators are coupled together in a so-called daisy chain arrangement.
In any of these and many other pressurized fluid systems, it is desirable to monitor a pressure of the pressurized fluid so that adjustments can be made to compensate for reductions in pressure occurring when pressurized fluid is removed from the system, such as by way of a fuel injection, and for other purposes. Commonly owned U.S. Pat. No. 7,296,474 to Shamine is directed to a fluid sensor having a low-pressure drain. In Shamine, a sensor has a sensor body enclosing a sensor element that senses a parameter of a pressurized fluid. A passageway fluidly communicates the sensor element with the pressurized fluid. A second passageway allows fluid that has leaked past a sealing surface to drain to a tank. Shamine is one example of a sensor connecting or mounting arrangement where leaks or seal failures are handled by providing a drain path between double “walls” of a housing or reservoir of the pressurized fluid system. A number of jurisdictions require “double-walled” fluid containment for certain types of fluids, notably combustible fluids such as fuel. Typical applications where a double-walled design is necessary or desirable include offshore oil or gas platforms and the like, and various other marine applications. While Shamine may work well for its intended purposes, there is always room for improvement.